The bifurcated view of open data on Data.gov will evaporate later this month and there will be an API to the entire catalog. You can also separate that catalog along geo and non-geo data if that's your preference. To get an early look at the direction we are heading, check out: http://geo.gov.ckan.org/dataset

Raw data is being merged with geo-data as we speak in this demo site. This is a work in progress, so you'll be seeing updates and upgrades as we implement them before we launch operationally with the new catalog in late May 2013.

Unfortunately, there seems to be no way to get a single list of dataset ids (or names) via a CKAN package_search query to catalog.data.gov, since the supported solr subset does not allow for the fl-parameter (which would get a subset of fields in each metadata record). Also the ckan legacy rest apis are redirected to package_search. So currently no way to get a list of datasets, whether geo or not.

https://explore.data.gov/catalog/raw
It still, however, has data in it that is associated to particular places. Like Toxics Release Inventories by state, or Earthquake plots. That, however, is not "geodata" by Data.gov's terminology.